This Ruth L. Kirschstein National Research Service Award Postdoctoral Research Training Grant renewal application is submitted in response to Program Announcement # PA-11-184 for applications to provide institutional T32 awards to train young researchers who will become independent investigators conducting research that addresses important problems in human health. The application requests continued resources to support four physician/scientists each year with MD or MD/PhD degrees who receive mentored research that focuses on the etiology, pathogenesis, and treatment of pediatric malignancies. The overall objective of this T32 program is to train new investigators who will improve the care of children with cancer. The rationale for the program is based on the substantial burden of pediatric cancer in the United States and the well-documented need to provide mentored career development support for young scientists that will enable them to become fully independent and productive laboratory researchers. As such, they will be poised to improve the health of children with cancer throughout the world by bringing state-of-the-art expertise to bear on problems such as inherited predispositions, environmental factors, the toxic and relatively non-specific nature of current therapies, and long-term adverse effects of mutagenic treatments. The design of this program involves harnessing the expertise of world-class research scientists who will serve as mentors for interdisiciplinary training. We have successfully implemented distinct training tracks for laboratory-based and clinical/translational investigators. We believe that the progress of this T32 program since its inception in 2007 demonstrates that UCSF has the vision, experience, and infrastructure to train the next generation of leaders in childhood cancer research. In this renewal application, we provide evidence that the Department together with the broader UCSF research community comprise an exceptional environment for preparing young investigators for productive careers in this field and describe a comprehensive plan for training and mentoring these individuals.